<topic>
	<head>
		<title>STDEV</title>
		<keywords>
			<keyword term="functions, STDEV" />
			<keyword term="aggregates, STDEV" />
			<keyword term="aggregate functions, STDEV" />
			<keyword term="STDEV aggregate" />
		</keywords>
		<links>
			<link href="Functions.html">Functions</link>
			<link href="Aggregate Functions.html">Aggregate Functions</link>
		</links>
	</head>
	<body>
		<summary>
			<p>
				Returns the statistical standard deviation of the specified expression in a group. <c>NULL</c> values are ignored.
			</p>
		</summary>

		<syntax>
			<code xml:space="preserve">STDEV ( expression )</code>
		</syntax>

		<parameters>
			<params>
				<param name="value">
					<p>
						An expression to determine the statistical standard deviation for.
					</p>
				</param>
			</params>
		</parameters>

		<returns>
			<p>
				The statistical standard deviation of all evaluated values of <c>expression</c> in a group. <c>NULL</c> values are ignored.
			</p>
		</returns>

		<remarks>
			<p>
				The <c>STDEV</c> aggregate function is limited to the following data types:
				<ul>
					<li>byte</li>
					<li>sbyte</li>
					<li>short</li>
					<li>ushort</li>
					<li>int</li>
					<li>uint</li>
					<li>long</li>
					<li>ulong</li>
					<li>decimal</li>
					<li>float</li>
					<li>double</li>
				</ul>
			</p>
		</remarks>
	</body>
</topic>
